Enable RPR Route Processor Redundancy on Cisco 4500 Series Switch

posted 17 May 2013, 07:56 by Tristan Self

Something I've done recently, the switch has been in for over a year, but was put in, in a hurry, and we'd never got round to finishing off the configuration fully until now.

It has two processor supervisor blades, but its always been running in RPR mode, as we now run VMware ISCSI traffic through it, it being in this mode means a supervisior failure would result in a 2 minute failover before traffic would flow to the secondary supervisor blade. Tollerable (just) for network traffic no so for ISCSI, we'd have some crashed or very sad virtual machines after that.

So I enabled SSO on the switch to get the seamless (near lossless) failover of the supervisors. This way we don't have to worry about a loss of traffic through the failover, and we don't get a break in the ISCSI traffic.

There are three modes: Cold, warm and hot of the redundancy.

These relate as:
 RPR The show module command displays Cold
 RPR+ The show module command displays Warm
 SSO The show module command displays Hot

Therefore we want to use SSO as it will give us virtually no downtime RPR+ means about a 30 second gap in traffic, and RPR means about 2 minutes, as we have to wait for the whole supervisor to boot up from scratch.

CITATION: https://supportforums.cisco.com/docs/DOC-4028

#show redundancy

Redundant System Information :
------------------------------
       Available system uptime = 14 weeks, 2 days, 6 hours, 27 minutes
Switchovers system experienced = 2
              Standby failures = 0
        Last switchover reason = active unit failed

                 Hardware Mode = Duplex
    Configured Redundancy Mode = RPR
     Operating Redundancy Mode = RPR
              Maintenance Mode = Disabled
                Communications = Up

Current Processor Information :
-------------------------------
               Active Location = slot 5
        Current Software state = ACTIVE
       Uptime in current state = 4 days, 22 hours, 51 minutes
                 Image Version = Cisco IOS Software, Catalyst 4500 L3 Switch Software (cat4500e-ENTSERVICESK9-M), Version 12.2(53)SG2, RELEASE SOFTWARE (fc1)
Technical Support:
http://www.cisco.com/techsupport
Copyright (c) 1986-2010 by Cisco Systems, Inc.
Compiled Tue 16-Mar-10 04:50 by prod_rel_team
                          BOOT = bootflash:cat4500e-entservicesk9-mz.122-53.SG2.bin,1;
        Configuration register = 0x2102

Peer Processor Information :
----------------------------
              Standby Location = slot 6
        Current Software state = STANDBY COLD
       Uptime in current state = 4 days, 22 hours, 50 minutes
                 Image Version = Cisco IOS Software, Catalyst 4500 L3 Switch Software (cat4500e-ENTSERVICESK9-M), Version 12.2(53)SG2, RELEASE SOFTWARE (fc1)
Technical Support:
http://www.cisco.com/techsupport
Copyright (c) 1986-2010 by Cisco Systems, Inc.
Compiled Tue 16-Mar-10 04:50 by
                          BOOT = bootflash:cat4500e-entservicesk9-mz.122-53.SG2.bin,1;
        Configuration register = 0x2102

 
Currently we are running in RPR mode, see here the bit of the configuration:
redundancy
 mode rpr
 main-cpu
  auto-sync standard

Now we want to turn on SSO so we do this:
 
# redundancy
 
# mode sso

 
Answer yes to rebooting the standby, once it has rebooted itself it will come back up in SSO mode.
You can watch it do its thing by starting terminal monitor.
 
# terminal monitor
Now check that it is all up and running, as it is in SSO mode, we should now wee that the software state is: "STANDBY HOT":
 

 # show redundancy
Redundant System Information :
------------------------------
       Available system uptime = 14 weeks, 2 days, 6 hours, 36 minutes
Switchovers system experienced = 2
              Standby failures = 1
        Last switchover reason = active unit failed

                 Hardware Mode = Duplex
    Configured Redundancy Mode = Stateful Switchover
     Operating Redundancy Mode = Stateful Switchover
              Maintenance Mode = Disabled
                Communications = Up

Current Processor Information :
-------------------------------
               Active Location = slot 5
        Current Software state = ACTIVE
       Uptime in current state = 4 days, 23 hours, 0 minutes
                 Image Version = Cisco IOS Software, Catalyst 4500 L3 Switch Software (cat4500e-ENTSERVICESK9-M), Version 12.2(53)SG2, RELEASE SOFTWARE (fc1)
Technical Support:
http://www.cisco.com/techsupport
Copyright (c) 1986-2010 by Cisco Systems, Inc.
Compiled Tue 16-Mar-10 04:50 by prod_rel_team
                          BOOT = bootflash:cat4500e-entservicesk9-mz.122-53.SG2.bin,1;
        Configuration register = 0x2102

Peer Processor Information :
----------------------------
              Standby Location = slot 6
        Current Software state = STANDBY HOT
       Uptime in current state = 2 minutes
                 Image Version = Cisco IOS Software, Catalyst 4500 L3 Switch Software (cat4500e-ENTSERVICESK9-M), Version 12.2(53)SG2, RELEASE SOFTWARE (fc1)
Technical Support:
http://www.cisco.com/techsupport
Copyright (c) 1986-2010 by Cisco Systems, Inc.
Compiled Tue 16-Mar-10 04:50 by
                          BOOT = bootflash:cat4500e-entservicesk9-mz.122-53.SG2.bin,1;
        Configuration register = 0x2102

 
 
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